Schlumberger Technology Corporation

Adrian Vuyk, Jr

Herve Ohmer

Mark W Brockman

Platon Koptilov

A method and apparatus for predictable downhole milling of a casing window having predetermined location, orientation, dimension and contour geometry. An elongate substantially rigid milling shaft has at least one casing window milling element in fixed relation therewith and has a pilot mill in articulated and rotary driven connection with the milling shaft. The milling shaft is in articulated and rotary driven connection with a rotary drive mechanism. The articulated connection of the pilot mill and milling shaft may incorporate an articulation control system to permit the pilot mill to be maintained substantially coaxial with the milling shaft so that its trajectory at a predetermined stage of window milling can be controlled by the milling shaft when positive guiding by a deflecting tool can no longer be ensured. The deflecting tool is adapted to be set within the well casing and defines an inclined pilot mill guide surface for guiding the pilot mill along a predetermined inclined trajectory for milling into the well casing. The deflecting tool incorporates a generally cylindrical bearing for guiding and providing rotational stabilization to the pilot mill during initial window milling to ensure the accuracy of the pilot bore being milled through the well casing and into the surrounding formation. During window milling the pilot mill guides the milling shaft so that the string mills of the milling shaft remove a portion of the pilot mill guide bearing and form a guide face of predetermined contour on the deflecting tool for guiding other tools through the casing window and into the lateral bore. The deflecting tool may be of tubular geometry so as to guide not only the pilot mill but also the string mill and may also receive the rotary drive motor for guiding and stabilizing thereof.

Method and apparatus for retrieving a deflecting tool

Disclosed is a tooth type rolling cutter earth boring drill bit with secondary cutting elements on the tooth surfaces. The secondary cutting elements provide additional, relatively sharp edges that help cut hard rock. The teeth also have convex radiused buttresses at their bases to reduce the stresses the teeth experience when drilling through extremely hard rock. This allows the tooth bit to survive the high loads encountered when drilling hard, tough rock formations, without breaking the teeth. The combination of teeth with secondary cutting elements and convex radiused buttresses at their base provide a tooth type rotary drill bit that has superior resistance to wear and breakage when drilling through hard, tough rock without significantly reducing the drilling rate of penetration when drilling through soft rock.

Tooth type drill bit with secondary cutting elements and stress reducing tooth geometry

A method and apparatus that comprises releasably securing a milling tool to a deflecting tool using a securing mechanism. The securing mechanism comprises a member that is adapted to be broken by milling action of the milling tool. In addition, in some arrangements, a protective mechanism protects abrasive inserts on a pilot mill of the milling tool.

Growing community of inventors

Missouri City, TX, United States of America

Adrian Vuyk, Jr